Commit b2e593e2 authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds
Browse files

x86, mm: unify exit paths in gup_pte_range() 

All exit paths from gup_pte_range() require pte_unmap() of the original
pte page before returning.  Refactor the code to have a single exit
point to do the unmap.

This mirrors the flow of the generic gup_pte_range() in mm/gup.c.

Link: http://lkml.kernel.org/r/148804251828.36605.14910389618497006945.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ef947b25

arch/x86/mm/gup.c

+20 −19
Original line number Diff line number Diff line
@@ -106,36 +106,35 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, 
		unsigned long end, int write, struct page **pages, int *nr)

{

	struct dev_pagemap *pgmap = NULL;

	int nr_start = *nr;

	pte_t *ptep;

	int nr_start = *nr, ret = 0;

	pte_t *ptep, *ptem;



	ptep = pte_offset_map(&pmd, addr);

	/*

	 * Keep the original mapped PTE value (ptem) around since we

	 * might increment ptep off the end of the page when finishing

	 * our loop iteration.

	 */

	ptem = ptep = pte_offset_map(&pmd, addr);

	do {

		pte_t pte = gup_get_pte(ptep);

		struct page *page;



		/* Similar to the PMD case, NUMA hinting must take slow path */

		if (pte_protnone(pte)) {

			pte_unmap(ptep);

			return 0;

		}

		if (pte_protnone(pte))

			break;



		if (!pte_allows_gup(pte_val(pte), write)) {

			pte_unmap(ptep);

			return 0;

		}

		if (!pte_allows_gup(pte_val(pte), write))

			break;



		if (pte_devmap(pte)) {

			pgmap = get_dev_pagemap(pte_pfn(pte), pgmap);

			if (unlikely(!pgmap)) {

				undo_dev_pagemap(nr, nr_start, pages);

				pte_unmap(ptep);

				return 0;

			}

		} else if (pte_special(pte)) {

			pte_unmap(ptep);

			return 0;

				break;

			}

		} else if (pte_special(pte))

			break;



		VM_BUG_ON(!pfn_valid(pte_pfn(pte)));

		page = pte_page(pte);

		get_page(page);
@@ -145,9 +144,11 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, 
		(*nr)++;



	} while (ptep++, addr += PAGE_SIZE, addr != end);

	pte_unmap(ptep - 1);

	if (addr == end)

		ret = 1;

	pte_unmap(ptem);



	return 1;

	return ret;

}



static inline void get_head_page_multiple(struct page *page, int nr)

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